1. Find the center of mass of a circular plate of radius 10.0 cm if there is a perfect hole 4.0 cm in diameter drilled at the coordinates (2.0, 0.0). The origin is at the center of the platter.

a. (0, -0.083)

b. (0.083, 0)

c. (0, 0.083)

d. (-0.083, 0)

2. Find the center of mass of three point masses arranged on the x axis: 3 kg at x = 3 cm, 2 kg at x = 1 cm and 1 kg at x = -1 cm.

a. 1.8

b. 1.33

c. 2

d. 1.67

3. What is the torque of a force of 10 N pushing a door open at a point 30 cm from its hinged edge if the force meets the door at an angle of 30?

a. 3

b. 15

c. 4.5

d. 1.5

4. Find the center of mass of the following masses at the indicated coordinates in meters: 3.0 kg at (2,1); 5.0 kg at (-1,3); 8.0 kg at (-1,-1); and 4.0 kg at (0, 3)

a. (1.1,.15)

b. (-1.1, -0.15)

c. (-0.35, 1.1)

d. (0.15, -1.1)